MEDRADSC 1B03 - Cellular Damage and Necrosis

types of cell adaptation

atrophy, hyperplasia, dysplasia, hypertrophy and metaplasia

atrophy

decrease in size of an organ or body part due to the shrinkage in the size of it's cells

atrophy is due to

reduced use, insufficient nutrition and/or age

hypertrophy

increase in size of an organ or body part due to the enlargement in the size of cells

hypertrophy is due to

increased workload on body part/organ

hyperplasia

increase in the size of an organ or body part due to an increase in the number of cells

hyperplasia cannot occur in

nervous cells and muscle cells

metaplasia

reversible change when one adult cell type is replaced by another adult cell type

metaplasia is due to

a response to chronic irritation, inflammation, infection or precancerous change

dysplasia

tissue in which cells vary in size and shape

dysplasia is due to

a response in chronic irritation, inflammation, infection or precancerous change

anaplasia

cells that are undifferentiated

anaplasia is associated with

malignancy

hypoxia

a decrease of oxygen supply to tissues

hypoxia is due to

ischemia, altitude, respiratory disease, anemia and cardiac disease

mechanical forces of injury

physical trauma of tissues

temperature extremes types

low intense heat, high intense heat and cold

low intense heat causes

heat stroke, partial thickness burns

high intense heat causes

coagulation

cold conditions

increased viscosity and induced vasoconstriction

electrical forces of injury

extensive tissue injury through electricity flowing through the body

radiation injury

how cells can become ionized through exposure to ionizing radiation

non-ionizing radiation injury

infrared, ultrasound waves, microwaves and lazer energy can all cause virbation of cells, leading to the production of thermal energy

ultraviolet radiation

UVA and UVB

ultraviolet radiation exposure - risks

sunburn, increase risk of calcium

chemical toxins - types

exogenous and endogenous

exogenous chemical toxins

chemicals from the environment that may cause injury to body systems

endogenous chemical toxins

toxins from inside the body due to a metabolic disorder

drugs - tissue injury

can overwhelm the body systems and cause liver failure

nutritional imbalances - tissue injury

excesses and deficiencies in nutrition can cause tissue injury through the development of diseases such as atherosclerosis and anorexia which could lead to starvation, anemia and widespread tissue damage

two types of outcomes of cellular injury

reversible and irreversible

events that occur after cell death

nucleus disintegrates, cells undergo lysis, cells release lysosomal/lytic enzymes, enzymes cause inflammation and damage of nearby cells and enzymes can diffuse into the blood stream

infarction

an area of cell death resulting from lack of oxygen

necrosis

death of cells or tissue within a living body

three types of necrosis

liquefaction, coagulative and caseous

liquefaction necrosis

cells liquify as a result of enzymes released

coagulative necrosis

gray, firm mass produced, this type of necrosis is due to hypoxia

caseous necrosis

cells transform into a cheese-like centre and can bind to calcium

gangrene

death of tissue associated with loss of blood supply

types of gangrene

dry, wet and gas

treatment for gangrene

removal/amputation of affected areas

dry gangrene - cause

occlusion

dry gangrene

part becomes dry, shrinks, turns brown and then black

wet gangrene

found in a part containing fluid and exposed to bacteria

gas gangrene

clostridium bacteria produces gas bubbles